Long-term Non-invasive Hemodynamic Evaluation of Left Endocardial Cardiac Resynchronization Therapy

Abstract

Background: Cardiac resynchronization therapy has 25% to 30% rate of “non-responder” patients. Endocardial cardiac resynchronizationtherapy (eCRT), in which the left ventricular catheter is implanted in the endocardium, would be an alternativefor these patients; however, its long-term outcome has not been investigated.Objectives: The aim of this study was the long-term non-invasive hemodynamic evaluation of eCRT in clinical responders.Methods: Patients implanted according to the criteria for resynchronization, using the Jurdham technique, with more than 6months after the implant, were included in the study. All were clinical responders. The hemodynamic response was evaluatedwith a cardiac function analyzer, which measures the left ventricular systolic intervals (preejection and ejection periods) andautomatically calculates an index of systolic function and estimates the ejection fraction (Systocor mod IS100). To assess themechanical efficacy of eCRT, the cardiac function during biventricular mode was compared with left bundle branch block(LBBB), either spontaneous or by single stimulation of the right ventricle, with patients as their own controls. At least 20beats were averaged in each stimulation mode and only changes >1% with p <0.01 were considered as clinically relevantand statistically significant.Results: Seventeen patients were included, with a median follow-up of 43 months, (9 to 78 months). Endocardial resynchronization,compared with LBBB ventricular activation, showed that all patients shortened the preejection period by an average of31 ms (15%), indicative of decreased interventricular dyssynchrony caused by LBBB. In all patients, systolic function indexincreased by 0.3 (23%) and the EF by 8.3%. In 12/17 of cases (71%) the ejective period increased on average 8.7 ms (2.9%),suggesting an increase in systolic volume. In all changes p was <0.01.Conclusions: Endocardial resynchronization therapy offers significant long-term hemodynamic improvement, detected bysystolic intervals.